1 files changed, 7 insertions, 1 deletions
diff --git a/compiler-rt/lib/fuzzer/dataflow/DataFlow.cpp b/compiler-rt/lib/fuzzer/dataflow/DataFlow.cpp
index 99863074d72..a79c796ac45 100644
--- a/compiler-rt/lib/fuzzer/dataflow/DataFlow.cpp
+++ b/compiler-rt/lib/fuzzer/dataflow/DataFlow.cpp
@@ -69,6 +69,7 @@ static const uintptr_t *FuncsBeg;
 static __thread size_t CurrentFunc;
 static dfsan_label *FuncLabels;  // Array of NumFuncs elements.
 static char *PrintableStringForLabel;  // InputLen + 2 bytes.
+static bool LabelSeen[1 << 8 * sizeof(dfsan_label)];
 
 // Prints all instrumented functions.
 static int PrintFunctions() {
@@ -89,7 +90,11 @@ static int PrintFunctions() {
   return 0;
 }
 
-static void SetBytesForLabel(dfsan_label L, char *Bytes) {
+extern "C"
+void SetBytesForLabel(dfsan_label L, char *Bytes) {
+  if (LabelSeen[L])
+    return;
+  LabelSeen[L] = true;
   assert(L);
   if (L <= InputLen + 1) {
     Bytes[L - 1] = '1';
@@ -103,6 +108,7 @@ static void SetBytesForLabel(dfsan_label L, char *Bytes) {
 static char *GetPrintableStringForLabel(dfsan_label L) {
   memset(PrintableStringForLabel, '0', InputLen + 1);
   PrintableStringForLabel[InputLen + 1] = 0;
+  memset(LabelSeen, 0, sizeof(LabelSeen));
   SetBytesForLabel(L, PrintableStringForLabel);
   return PrintableStringForLabel;
 }